Telewest (previously Telewest Broadband and Telewest Communications) was a cable internet, broadband internet, telephone supplier and cable television provider in the United Kingdom. It was listed on the London Stock Exchange, and was also once a constituent of the FTSE 100 Index.

In March 2006, Telewest merged with fellow cable telecom company NTL, and created "NTL:Telewest", which then also merged with Virgin Mobile and Virgin.net in June 2006, creating the United Kingdom's first "quadruple play" telecom provider, offering television, internet, landline phone and mobile phone services. In February 2007, NTL:Telewest was rebranded as Virgin Media.

Telewest originated in Croydon in 1984 under the name "Croydon Cable". United Cable, of Denver, acquired Croydon Cable in 1988. Franchises extended the company scope into Edinburgh and the southwest and southeast of England. In 1989, United Cable merged with United Artists Cable International.

In May 1991, United Artists announced a merged deal with its largest shareholder Tele-Communications Inc. (TCI), to form the largest cable operator in the United States; the deal was valued at $142.5m, and by June the deal was improved. The deal was finalised a week later on 8 June 1991, with TCI acquiring the remaining 46% of United Artists, to allow full control.

TCI and US West announced a joint venture, and in 1992, the joint venture company became Telewest Communications, a combination of the names of both founding companies. In June 1995, Telewest merged with SBC CableComms, adding franchises in the Midlands and North West serving 1.3 million homes. During this time Telewest founded a consortium called Cable Internet. This consisted of the major cable companies in the United Kingdom working together to provide a national Internet access service.

In March 1998, Telewest announced a merger with General Cable, and acquired the outstanding interest in Birmingham Cable, adding a further 1.7 million franchise homes in Yorkshire, west London and Birmingham. Telewest purchased the remaining 50% stake in Cable London from NTL in August 1999, adding 0.4 million franchise homes in North London.

Telewest merged with Flextech in April 2000, and in November, extended its cable network with the acquisition of Eurobell, taking the total number of homes passed to 4.9 million. The company later became known as "Telewest Broadband" in a rebrand during 2001. Telewest experienced financial difficulties in subsequent years, owing to the debts incurred as a result of constructing its cable network and acquiring other cable companies and assets. Notably, the Eurobell acquisition had been funded by an equity based deal, with a cash option; the poor performance of the company's stock meant that the cash option was favourable, and the company was not able to cover the call.

In September 2003, Telewest restructured itself, by swapping its unsecured debt for 98.5% of its shares. The London Stock Exchange then delisted the consolidated shares. Major Telewest shareholders included Huff and Liberty Media (run by cable tycoon John Malone).